At least one embodiment of the invention relates to an antenna rod for a rod antenna on a motor vehicle, to be affixed and electrically connected with the electromechanical base connector of a low plastic base part attached to the vehicle body. In at least one embodiment, this antenna contains the further antenna circuit that is connected with the electromechanical base connector, which connector is connected to a plastic rod on which an antenna coil is affixed.
One antenna rod is known, for example, as a short-rod antenna, from DE 102004053354A1, particularly for radio reception in motor vehicles. This antenna rod is a short aerial, especially a vehicle radio aerial, that comprises a pedestal (2) and a shaft (3). The pedestal is located on the vehicle body work and is flexible, while the shaft is rigid. The shaft connection point is directly on the switching module via a connection line.
The antenna rod is attached to a plastic part and forms the high frequency HF radiator. Provisions are made to configure the winding at differentiated pitch, in order to utilize the shaft not only for the frequencies of radio but also for operation in the frequencies of mobile telephony—in the 900 MHz and in the 1.8 GHz range.
For use in motor vehicles, the construction height of such antennas is of particular importance. They are preferably used on the roof of the vehicle and represent a hindrance if their length is too long, particularly in parking garages having a low construction height and so-called double-parkers.
The radiator bandwidth of electrically short rod antennas increases by approximately cubing the length of the antenna rod with reference to the free-space wavelength of the operating frequency. In contrast to the conditions that prevail in the frequency range of AM radio, this law represents a particular difficulty, when designing very short rod antennas, in the frequency range of USW radio at a bandwidth of approximately 20 MHz, in connection with the ambient noise that is already low in this frequency range. The term USW can include the FM broadcast band or other bands known in the art. Antennas according to the state of the art generally possess a length of 40 cm. In addition, there is the demand for being able to produce such antenna rods, which are subject to particularly great cost pressure in vehicle technology, as cost-advantageously as possible.
It is therefore the task of one embodiment of the invention to indicate an antenna rod that on the one hand, that delivers the greatest possible reception voltage in the frequency range of ultra short wave USW radio, at the smallest possible length, and also allows operation for the radio services at higher frequency, as well as particularly cost-advantageous production.